1. Field of the Invention
The present invention relates to a method for producing fine metal hydroxide particles, particularly to a method for producing fine magnesium hydroxide particles.
2. Description of the Related Art
Hithertofore, polymeric materials and thermoplastic resins have been used in various fields as materials for electrical and electronic equipment parts, housings, and the like. When polymeric materials are used as covering materials of OA equipment such as television sets and personal computers, the polymeric materials are required to have flame retardancy from the viewpoint of safety.
As a method for imparting flame retardancy to a polymeric material, a flame retardant is added to the polymeric material. Typical flame retardants include those based on halogen, phosphorus, and inorganic particles. However, halogen flame retardants have many problems in an environmental aspect such as generation of halogen gas and black smoke during combustion and generation of dioxin during incineration. Further, phosphorus flame retardants also have problems in an environmental aspect such as generation of phosphine gas, and in addition, they have a problem such as high cost and concern about the supply of phosphate rock which is a raw material.
On the other hand, metal hydroxides representing inorganic particle flame retardants such as fine magnesium hydroxide particles are harmless and have few problems in an environmental aspect. The metal hydroxides further have features such as low cost and abundant raw material resources and can solve the problems of both halogen flame retardants and phosphorus flame retardants.
For example, Japanese Patent Application Laid-Open No. 2002-348574 discloses a method for producing magnesium hydroxide particles including producing a coprecipitate of magnesium hydroxide by neutralization, producing fine magnesium hydroxide particles by hydrothermal reaction, and surface-treating the fine magnesium hydroxide particles, followed by filtrating, water washing, drying, and grinding.